if your doing it dry start why not let it fill in befor you flood it? it will grow faster with it not being flooded so if there is no rush like fish coming in the mail or anything simaler then let it get full imo. haveing it vented helps bring in new air which isnt bad! you just have to make sure it doesnt dry out. are u doing co2 on this tank? if so have u thought about keeping the seranwrap on there and adding co2 to help it along even more?
btw i like that u thought outside the box an had the tank tilted so it wasnt ˝ submerged ˝dry. id really wait though on flooding it unless you have to rush it.